Same weight as you and I use iSonic 117 Wide with 7.7/8.6/11.0 m2 sails. Planning at full speed in winds from 7 up to 18 knots.

Tried iSonic 127 and it's clearly 1 size larger than iSonic 117 wide. However, I did not experienced any gain in lower planning threshold with lighter winds IMHO.
With 9.2 m2 sail as largest and for your light weight, no need to go to iSonic 127, the 117 should be plenty enough. What is your other high-wind slalom board(s) ?

For 117L 80cm, mainly used with 8.4m and 9.2m TR9, what Fin is suitable?
Considering Z -S 44cm and 46cm -> quite high price......
or T43 44cm and 46cm -> used from 30cm to 42cm for other board, quite lovely speed indeed...but comparing to Carbon fin... weight more.....